Android ExpandableListView的下拉刷新实现

著论准过秦，作赋拟子虚。这篇文章主要讲述Android ExpandableListView的下拉刷新实现相关的知识，希望能为你提供帮助。
该控件的修改时根据PullToRefreshList的机制修改
【Android ExpandableListView的下拉刷新实现】下面是对ExpandableListView的扩展

package com.up91.gwy.view.componet; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import com.up91.gwy.R; import android.content.Context; import android.util.AttributeSet; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.ViewGroup; import android.view.animation.LinearInterpolator; import android.view.animation.RotateAnimation; import android.widget.AbsListView; import android.widget.ExpandableListView; import android.widget.AbsListView.OnScrollListener; import android.widget.ImageView; import android.widget.ListAdapter; import android.widget.ProgressBar; import android.widget.RelativeLayout; import android.widget.TextView; public class PullToRefreshExpandableListView extends ExpandableListView implements OnScrollListener { private static final String TAG = "PullToRefreshExpandableListView"; private static final int TAP_TO_REFRESH = 1; private static final int PULL_TO_REFRESH = 2; private static final int RELEASE_TO_REFRESH = 3; private static final int REFRESHING = 4; private OnRefreshListener mOnRefreshListener; private OnScrollListener mOnScrollListener; private LayoutInflatermInflater; private RelativeLayoutmRefreshView; private TextView mRefreshViewText; private ImageView mRefreshViewImage; private ProgressBar mRefreshViewProgress; private TextViewmRefreshViewLastUpdated; private int mCurrentScrollState; private int mRefreshState; private RotateAnimation mFlipAnimation; private RotateAnimation mReverseFlipAnimation; private int mRefreshViewHeight; private int mRefreshOriginalTopPadding; private int mLastMotionY; private boolean isInInitState; public PullToRefreshExpandableListView(Context context) { super(context); init(context); } public PullToRefreshExpandableListView(Context context, AttributeSet attrs) { super(context,attrs); init(context); } public PullToRefreshExpandableListView(Context context,AttributeSet attrs, int defStyle) { super(context,attrs,defStyle); init(context); } private void init(Context context){ mFlipAnimation = new RotateAnimation(0,-180, RotateAnimation.RELATIVE_TO_SELF,0.5f, RotateAnimation.RELATIVE_TO_SELF,0.5f); mFlipAnimation.setInterpolator(new LinearInterpolator()); mFlipAnimation.setDuration(250); mFlipAnimation.setFillAfter(true); mReverseFlipAnimation = new RotateAnimation(-180,0, RotateAnimation.RELATIVE_TO_SELF,0.5f, RotateAnimation.RELATIVE_TO_SELF,0.5f); mReverseFlipAnimation.setInterpolator(new LinearInterpolator()); mReverseFlipAnimation.setDuration(250); mReverseFlipAnimation.setFillAfter(true); mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); mRefreshView = (RelativeLayout) mInflater.inflate(R.layout.pull_to_refresh_header, this,false); mRefreshViewText = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_text); mRefreshViewImage = (ImageView) mRefreshView.findViewById(R.id.pull_to_refresh_image); mRefreshViewProgress = (ProgressBar) mRefreshView.findViewById(R.id.pull_to_refresh_progress); mRefreshViewLastUpdated = (TextView) mRefreshView.findViewById(R.id.pull_to_refresh_updated_at); mRefreshViewImage.setMinimumHeight(50); mRefreshView.setOnClickListener(new OnClickRefreshListener()); mRefreshOriginalTopPadding = mRefreshView.getPaddingTop(); mRefreshState = TAP_TO_REFRESH; addHeaderView(mRefreshView); super.setOnScrollListener(this); measureView(mRefreshView); mRefreshViewHeight = mRefreshView.getMeasuredHeight(); } private void measureView(View child){ ViewGroup.LayoutParams p = child.getLayoutParams(); if(p == null){ p = new ViewGroup.LayoutParams( ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT ); } int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0+0, p.width); int lpHeight = p.height; int childHeightSpec; if(lpHeight > 0){ childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); }else{ childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec,childHeightSpec); } private class OnClickRefreshListener implements OnClickListener{ @Override public void onClick(View v) { if(mRefreshState != REFRESHING){ prepareForRefresh(); onRefresh(); } } } public interface OnRefreshListener{ public void onRefresh(); } @Override protected void onAttachedToWindow() { super.onAttachedToWindow(); setSelection(1); } @Override public void setAdapter(ListAdapter adapter) {super.setAdapter(adapter); setSelection(1); } @Override public void setOnScrollListener(OnScrollListener l) { mOnScrollListener = l; } public void setOnRefreshListener(OnRefreshListener onRefreshListener){ mOnRefreshListener = onRefreshListener; } public void setLastUpdated(CharSequence lastUpdated){ if(lastUpdated != null){ mRefreshViewLastUpdated.setVisibility(View.VISIBLE); mRefreshViewLastUpdated.setText(lastUpdated); }else{ mRefreshViewLastUpdated.setVisibility(View.GONE); } } public boolean onTouchEvent(MotionEvent event) { final int y = (int) event.getY(); switch (event.getAction()) { case MotionEvent.ACTION_UP: if (!isVerticalScrollBarEnabled()) { setVerticalScrollBarEnabled(true); } if (getFirstVisiblePosition() == 0 & & mRefreshState != REFRESHING) { if ((mRefreshView.getBottom() > mRefreshViewHeight || mRefreshView.getTop() > = 0) & & mRefreshState == RELEASE_TO_REFRESH) { // Initiate the refresh mRefreshState = REFRESHING; prepareForRefresh(); onRefresh(); } else if (mRefreshView.getBottom() < mRefreshViewHeight || mRefreshView.getTop() < 0) { // Abort refresh and scroll down below the refresh view resetHeader(); setSelection(1); } } break; case MotionEvent.ACTION_DOWN: mLastMotionY = y; break; case MotionEvent.ACTION_MOVE: applyHeaderPadding(event); break; } return super.onTouchEvent(event); } private void applyHeaderPadding(MotionEvent ev) { final int historySize = ev.getHistorySize(); // Workaround for getPointerCount() which is unavailable in 1.5 // (it‘s always 1 in 1.5) int pointerCount = 1; try { Method method = MotionEvent.class.getMethod("getPointerCount"); pointerCount = (Integer)method.invoke(ev); } catch (NoSuchMethodException e) { pointerCount = 1; } catch (IllegalArgumentException e) { throw e; } catch (IllegalAccessException e) { System.err.println("unexpected " + e); } catch (InvocationTargetException e) { System.err.println("unexpected " + e); } for (int h = 0; h < historySize; h++) { for (int p = 0; p < pointerCount; p++) { if (mRefreshState == RELEASE_TO_REFRESH) { if (isVerticalFadingEdgeEnabled()) { setVerticalScrollBarEnabled(false); } int historicalY = 0; try { // For Android > 2.0 Method method = MotionEvent.class.getMethod( "getHistoricalY", Integer.TYPE, Integer.TYPE); historicalY = ((Float) method.invoke(ev, p, h)).intValue(); } catch (NoSuchMethodException e) { // For Android < 2.0 historicalY = (int) (ev.getHistoricalY(h)); } catch (IllegalArgumentException e) { throw e; } catch (IllegalAccessException e) { System.err.println("unexpected " + e); } catch (InvocationTargetException e) { System.err.println("unexpected " + e); } // Calculate the padding to apply, we divide by 1.7 to // simulate a more resistant effect during pull. int topPadding = (int) (((historicalY - mLastMotionY) - mRefreshViewHeight) / 1.7); mRefreshView.setPadding( mRefreshView.getPaddingLeft(), topPadding, mRefreshView.getPaddingRight(), mRefreshView.getPaddingBottom()); } } } } private void resetHeaderPadding() { mRefreshView.setPadding( mRefreshView.getPaddingLeft(), mRefreshOriginalTopPadding, mRefreshView.getPaddingRight(), mRefreshView.getPaddingBottom()); } private void resetHeader() { if (mRefreshState != TAP_TO_REFRESH) { mRefreshState = TAP_TO_REFRESH; resetHeaderPadding(); // Set refresh view text to the pull label mRefreshViewText.setText(R.string.pull_to_refresh_tap_label); // Replace refresh drawable with arrow drawable mRefreshViewImage.setImageResource(R.drawable.ic_pulltorefresh_arrow); // Clear the full rotation animation mRefreshViewImage.clearAnimation(); // Hide progress bar and arrow. mRefreshViewImage.setVisibility(View.GONE); mRefreshViewProgress.setVisibility(View.GONE); } } public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { // When the refresh view is completely visible, change the text to say // "Release to refresh..." and flip the arrow drawable. if (mCurrentScrollState == SCROLL_STATE_TOUCH_SCROLL & & mRefreshState != REFRESHING) { if (firstVisibleItem == 0) { mRefreshViewImage.setVisibility(View.VISIBLE); if((mRefreshView.getBottom() > mRefreshViewHeight + 20 || mRefreshView.getTop() > = 0) & & mRefreshState == PULL_TO_REFRESH){ mRefreshViewText.setText(R.string.pull_to_refresh_release_label); mRefreshViewImage.clearAnimation(); mRefreshViewImage.startAnimation(mFlipAnimation); mRefreshState = RELEASE_TO_REFRESH; }else if(mRefreshState == RELEASE_TO_REFRESH & & mRefreshView.getBottom() < mRefreshViewHeight + 20){ mRefreshViewImage.setVisibility(View.GONE); resetHeader(); }else if(mRefreshView.getBottom() == mRefreshViewHeight& & mRefreshState == TAP_TO_REFRESH){ //不作为 mRefreshViewImage.setVisibility(View.GONE); resetHeader(); } else if(mRefreshView.getBottom() < mRefreshViewHeight + 20 & & mRefreshState == TAP_TO_REFRESH){ mRefreshViewText.setText(R.string.pull_to_refresh_pull_label); mRefreshState = PULL_TO_REFRESH; mRefreshViewImage.clearAnimation(); mRefreshViewImage.startAnimation(mReverseFlipAnimation); } } else { mRefreshViewImage.setVisibility(View.GONE); resetHeader(); } } else if (mCurrentScrollState == SCROLL_STATE_FLING & & firstVisibleItem == 0 & & mRefreshState != REFRESHING) { setSelection(1); } if (mOnScrollListener != null) { mOnScrollListener.onScroll(view, firstVisibleItem, visibleItemCount, totalItemCount); } } public void onScrollStateChanged(AbsListView view, int scrollState) { mCurrentScrollState = scrollState; if (mOnScrollListener != null) { mOnScrollListener.onScrollStateChanged(view, scrollState); } } public void prepareForRefresh() { resetHeaderPadding(); mRefreshViewImage.setVisibility(View.GONE); // We need this hack, otherwise it will keep the previous drawable. mRefreshViewImage.setImageDrawable(null); mRefreshViewProgress.setVisibility(View.VISIBLE); // Set refresh view text to the refreshing label mRefreshViewText.setText(R.string.pull_to_refresh_refreshing_label); mRefreshState = REFRESHING; } public void onRefresh() { if (mOnRefreshListener != null) { mOnRefreshListener.onRefresh(); resetHeader(); } } public void onRefreshComplete(CharSequence lastUpdated) { setLastUpdated(lastUpdated); onRefreshComplete(); } public void onRefreshComplete() {resetHeader(); // If refresh view is visible when loading completes, scroll down to // the next item.if (mRefreshView.getBottom() > 0) { invalidateViews(); setSelection(1); } } }

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